CHESAPEAKE, Virginia (CNN) --Convicted sniper John Allen Muhammad trained his teenage accomplice to kill by sending him on a personal murder mission, eight months before their killing spree last fall, two psychiatrists testified Wednesday.

Lee Boyd Malvo, 18, is accused of killing FBI analyst Linda Franklin at a Home Depot in Falls Church, Virginia.

Her death was one of 10 fatal sniper attacks that terrified Washington, D.C., and outlying areas of Virginia and Maryland. Three other people were wounded.

Muhammad, 42, was convicted of murder last month in one of the killings. The jury recommended a death sentence.

Malvo, who was 17 at the time of the attacks, is charged with capital murder, terrorism and use of a firearm in the commission of a felony in Franklin's death on October 14, 2002.

Prosecutors have long believed Muhammad and Malvo were responsible for the death of Keenya Cook, the niece of a woman Muhammad blamed for breaking up his family.

But Wednesday was the first time Malvo's account of the shooting had been made public. Cook's aunt, Isa Nichols, was a close friend of Muhammad's wife.

The doctors testified in support of the defense's contention that Malvo was legally insane during the sniper shootings.

Cook, 21, was shot in the face at point-blank range at a house in Tacoma, Washington, on February 16, 2002.

The doctors said Malvo told them Muhammad ordered the attack three hours beforehand. They called Muhammad an imposing father figure who sought to brainwash Malvo and turn him into a one-man army.

"This was his first mission," defense psychiatrist Neil Blumberg testified. Malvo, he said, "was afraid to say he couldn't do it."

According to the account the doctors related, Muhammad told Malvo that Nichols broke up his family, stole $1 million from his business, and stole money from numerous Muslim families. There is no evidence to support the claims.

According to Malvo, Muhammad told him he wanted to kill one of Nichols' relatives every year to retaliate for the loss of his three children.

The doctors testified that Muhammad dressed his apprentice in dark clothing.

The teenager chatted with Cook, who he described as friendly, for several minutes at her front door, then pulled a .45-caliber pistol and shot her in the face.

He ran two blocks, called Muhammad on a walkie-talkie, and tried to calm himself down, according to the account the doctors related.

Right from wrong

Blumberg and psychiatrist Diane Schetky said Malvo did not know right from wrong during the sniper spree. Their testimony is expected to be the cornerstone of the defense case.

Under Virginia law, the inability to tell right from wrong is the key factor in determining sanity. Blumberg also said Malvo was not able to resist the impulse to kill, a second test of insanity.

But the two defense experts differed over whether Malvo knew right from wrong when he shot Cook.

Schetky testified Malvo did, and that the killing someone point-blank was part of his training. She said Malvo was so upset immediately after shooting Cook that he soiled his pants.

Blumberg said Malvo was not able to distinguish right from wrong at the time.

Prosecution attorneys have challenged the insanity defense and the view that Muhammad indoctrinated Malvo.

According to Blumberg, Muhammad indoctrinated Malvo by desensitizing him to violence, playing him tape-recorded speeches even while Malvo slept, isolating Malvo from family and friends, subjecting him to a rigorous physical regimen and controlling his diet and sleep.

"There was no right or wrong," Blumberg testified. "Right is what Muhammad tells him is right. He's basically a soldier in Muhammad's war against America."

Muhammad offered Malvo the belonging and stability that was missing for much of his childhood, Blumberg said.

"In exchange, Lee does any and everything that is requested of him. From Lee's perspective, rejection is a fate worse than death. He would rather be dead than be without Muhammad."

Blumberg said he spent about 50 hours meeting with Malvo on 20 different occasions following his arrest. He said Malvo at first was cooperative but odd, frequently laughing at inappropriate moments.

He said Malvo talked in political and sociological jargon and that the conversations got progressively worse. The turning point, he said, was when Malvo's former teacher visited him at the Fairfax County, Virginia, jail.

Schetky testified that during her psychiatric evaluation of Malvo, he did not act like someone facing serious charges, a behavior she said was evident in the courtroom Wednesday.

"He's sitting there doodling like a child in preschool," she said. "I think he was very much totally apart from his feelings.

"He talked about his crimes in a very mechanical way with no feelings. He used to have compassion. He used to care. He used to feel hurt. He used to feel other people's hurt. This was all walled off under Mr. Muhammad's tutelage."

She said Malvo blamed himself for the pair's capture because he had fallen asleep the night of the arrest at an interstate rest stop in Maryland.